Toward Development of the Tornado Impact-Community Vulnerability Index

Abstract

Given the recognition that not only physical processes, but also social, political, and economic aspects of hazards determine vulnerability to and impact of an event, a classification system that addresses those factors is needed. Current classifications for natural disasters, such as the Fujita Scale for tornadoes and the Saffir-Simpson hurricane scale, focus on the physical properties of the event, not the impact on a community. Pre-event vulnerability to a natural hazard is determined by factors such as age, race, income, gender, infrastructure, density of the built environment and health of the industrial base. The behavior of residents in the community, construction quality of shelters, and warning system effectiveness also affect vulnerability. If vulnerability is influenced by such factors, post-event impact should be, at least in part, as well. The goal of this research was to develop the Tornado Impact- Community Vulnerability Index (TICV) that utilizes variables such as the number of persons killed, economic impacts, and social vulnerability to describe to the level of impact a tornado event has on community. As tornadoes that strike unpopulated areas are often difficult to classify, even in the traditional sense, the TICV will take into consideration only events that strike communities defined as “places” according to the U.S. Census Bureau. By assigning a rating to the impact, this index will allow the severity of the storm to be understood in terms of its effect on a specific community and hence its impact, rather than in terms of its physical strength.